Plot Twist : Hollywood: A veteran screenwriter shows he still has what it takes. At 83, he has sold a movie script in a deal promising half a million dollars when shooting begins.

Screenwriter Herb Meadow first encountered ageism, Hollywood style, sitting in his agent’s office. He was 47 years old.

“The phone rang with a producer calling about a writer he wanted to hire,” Meadow recalls. “My agent said, ‘You’re not going to hire him. He’s 47.’

“I said to him, ‘Do you know how old I am?’ ”

Even with his agent’s reassurances, Meadow was jolted. “Up until that time I had never encountered ageism or the subject in this town,” he said. Only later did he realize that Hollywood’s perceived bias against writers above a certain age had become the industry’s “weapon to thin out the ranks and get rid of people who were troublesome.”

Meadow admits he’s been troublesome most of his career. (“I changed agents like I changed socks.”) But so far, ageism hasn’t gotten rid of him. He’s 83 now.

True, he doesn’t work constantly as he once did. Nor does his current agent return his phone calls promptly. But neither youthfulness nor agency aggressiveness--two of the biggest assets for a Hollywood career--were necessary to snag Meadow the deal of his life. After 50 years in Hollywood, his days as a player long over and his name virtually absent from movie and television credits for the past decade and a half, Meadow accomplished the sort of thing that fuels writers’ dreams: On his own, he sold a screenplay for a promised half a million dollars.

And it’s not even some trendy blood-soaked journey through the urban underbelly. It’s a fictional account of a real-life 18th-Century pirate named Anne Bonney and her struggles to survive in a very male world.

“We love period pieces,” says Fausto Calegarini, vice president of Cinemagic Pictures North Inc., a fledgling independent production company that bought the rights to “Anne of the Southern Main” and hopes to start production next spring. “We decided right away to go and try to buy it.”

Meadow and Calegarini hammered out the details over dinner a year ago at one of Meadow’s favorite haunts, the Mandarin, an unprepossessing Chinese restaurant with windows that look out on the San Vicente Boulevard edge of Beverly Hills. But it was only this past September that the deal was officially struck.

“He’s the grandpa I never had,” says Calegarini, 34, of Meadow. “I talk to him every day.”

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It’s hardly the biggest deal in town. It’s a fraction of what uber- screenwriters Joe Eszterhas ($3 million for “Basic Instinct”) and Shane Black (who recently sold “The Long Kiss Goodnight” for $4 million) command for “spec” scripts sold on the open market. And unlike them, Meadow sees none of his money upfront. Although he got $4,310 for an option, Meadow won’t be paid a lump sum of $500,000 until the eve of production--always a tenuous date until cameras actually roll. “Once you get into this business, you learn to wait,” Meadow says wisely.

But for a guy who was in his prime in 1945 when Hedy Lamarr would call him in the middle of the night, his deal is a sweet and surprising triumph.

“I am trapped by a constant of nature,” Meadow says soberly of the aging process that has crippled his body but not his creativity. “All I ask is that I be allowed to work productively until it’s time for me to go.”

He lives surrounded by the success that he has made for himself through the years. In his study, on top of his immaculately dusted bookshelves, are scripts of plays and movies he has written, some produced, some not.

He has penned 37 feature-length movie scripts--12 of which have been filmed. “I want you to know, young woman, I’ve had only one bad review in my life,” he says in the sonorous voice that got him a job in New York radio when he was a mere tyke in his 20s.

He prefers writing in longhand but he’s made the obligatory shift to a computer. “It became a trend,” he grumbles. “Like flared pants.”

In true L.A. style, he shares a lofty Spanish-style house with his second wife--now his ex. “We fought like cats and dogs for six years,” he says. “So we got divorced.” Now they peacefully cohabit what is actually a duplex connected by an open doorway--he lives on one side, she on the other.

The true love of his life is a woman with dark swept-back hair in a framed photograph on a wall. “That’s my late wife,” he says, gazing at the picture of his spouse of 43 years. “She was indeed a beautiful person. She died in 1980.”

He has one son--who is now a lawyer--and had a mentally handicapped daughter who died four years ago in an institution. “She didn’t know how to do anything but open packages,” he says.

He doesn’t drive anymore, and his cocky New York strut is long gone. Hobbled by constant hip pain and numb feet, he walks only when necessary and then with a cane.

He grew up in Brooklyn, and dropped out of the ninth grade but retained a voracious appetite for reading. During Prohibition he was a runner for a bootlegger and gangster.

One day, he recounts, he was making a delivery to a tiny radio station in Brooklyn when he discovered the radio announcer passed out from drinking. The manager of the station, hearing Meadow’s voice, ordered him onto the air. “Apparently I have a great radio voice,” he says matter-of-factly.

Later he worked as a writer of 350 episodes of a radio soap called “Valiant Lady” before he made his way to Hollywood to pursue a career in screenwriting. “That’s a wonderful story,” he says with a smile over lunch at the Mandarin. School dropout or not, he’s given to verbal flourishes and long, vivid tales. “Have you got all day?” he asks.

The short version: An actor friend auditioning for the then-unscripted movie “The Robe” asked Meadow to write him some lines. After the audition, the actor called him and said, “I gave the performance of my life--but they want you.”

Meadow went off to L.A. to write what he says was the first draft script for “The Robe.” “There were 11 writers that I know of,” he says. “But (Philip) Dunne is credited with it.”

It was his first taste of frustration with the credit system of Hollywood--but it was also his first taste of the lifestyle and the work. From the moment he arrived in September, 1944, and glimpsed his first palm tree he was intoxicated with Hollywood and the industry. “I said, ‘I ain’t going back.’ ” Since then, he has never been forced to do anything for money other than write.

In the Hollywood of his heyday, writers of all ages held forth at studio commissary tables and vied to see who was the most nattily dressed. Malibu was truly the beach of postcard dreams. As for agents, they not only returned your calls, they fed you spaghetti when you were low on money.

On balance, Hollywood has given him success, an affluent lifestyle, a resume full of credits. In television he is credited as a co-creator of the famous series “Have Gun, Will Travel.” In film, he wrote scripts with titles such as “Redhead From Wyoming” (starring Maureen O’Hara), “Stranger on Horseback” (starring Joel McCrae) and “The Strange Woman,” a 1946 film starring Hedy Lamarr. On the bad side, he saw scripts that he loved languish in limbo.

He drifted into television (the money was better, he says) and worked there for 30 years. Though he is proud of “Have Gun, Will Travel,” he eventually came to despise television ensemble writing. “It’s degrading, it’s disgusting,” he says.

His last credit was the desultory “Curse of King Tut’s Tomb,” which aired on television in the late ‘70s. “What I wrote was not what they did,” he contends.

But in fact, his last stab at television was the Anne Bonney script--written in the wake of his wife’s death 14 years ago to combat his crushing sorrow. He says a television executive asked him to write a script based on a story written by two other people. The subject was Anne Bonney. He threw out the old story, wrote a script in two months and had it proclaimed brilliant by the executive--only to see it scuttled within a week because it would have been too costly for the network to produce.

It was around that time that creeping old age conspired to dry him up as a writer.

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“I ended up breaking the rule I tell all young writers,” he says. “You must write every day.”

Eventually he found his spirit again, channeling it into a children’s book and retooling the Anne Bonney story into a movie.

His pirate tale is less a costume drama and more a portrait of a society.

“Piracy is not what people think--Errol Flynn letting out a whoop and climbing up some rigging.” (Though Meadow wrote something like that for Errol Flynn once.) “Pirates were very interesting people. They were the unemployed of today. They mugged you, stole from you, burgled your house--because they had to eat, not because they enjoyed themselves. They had to survive.”

Meadow continues to survive nicely even though his days of being a hot property are far behind him.

“Let’s be honest,” he says. “If you were an agent and you were told that this 83-year-old guy just sold a screenplay at a very nice price, you wouldn’t be interested. You are interested in me only on the amount of earning years that are left in me.”

As for his personal life, he says, “I don’t live a social life anymore. I don’t care about the social life out here today. And second, many of my friends have done me dirty--they died. Some are better for it,” he says without skipping a beat. “Some I miss.”